To add a headshot and other images to an IMDb page, you'll need an IMDbPro membership.
If you already have joined IMDbPro and have an IMDb page, you may upload photos almost immediately. First, claim your page to link your IMDb name page to your account. Next, click on the Photos link on the My Page menu which is in the navigation bar at the top of every IMDbPro page (alternatively click here) and follow the upload instructions there.
If you do not have an IMDbPro membership, you can sign up for a free trial.
If you do not already have an IMDb page, you will be given the option to create one when you claim your page.
After claiming your page and adding photos, you may also add further information.
To add an image to an IMDb title page (i.e. movie, TV show, TV episode, video game, etc.) simply select the "Add Image" option located at the end of the image gallery. For more information, please see IMDb Title Images: Frequently Asked Questions